The present invention relates to porous building materials having a surface thereon that is reinforced by paper. Such materials commonly include a vapor barrier, and in all successful materials heretofore, the vapor barrier has been applied to the outside surface of the paper usually in the form of a metal foil. The metal foil was used heretofore, not only to provide a vapor barrier, but also to provide a protection against the spread of a flame caused to impinge upon the outside surface of the building material.
It is possible that other constructions of building insulation materials have been proposed heretofore, and with which we are not aware. Regardless of any such proposal, however, it is an object of the present invention to provide a new and improved method of providing a vapor barrier in building materials, as for example, insulation, wall board, ceiling boards, etc..
Another object of the present invention is the provision of new and improved building materials, as for example, an insulation material, a wall board or ceiling board having an impermeable membrane therein and which greatly and inexpensively reduces the flame spread rate of the surface of the materials.
Another object of the invention is the provision of a new and improved building material wherein the impermeable membrane is positioned between the main body portion of the building material and an outside protective paper layer.
Other objects and advantages of the present invention will become apparent to those skilled in the art to which the invention relates from the following description of several preferred embodiments described with reference to the accompanying drawings.